Antisense technology provides a means for modulating the expression of one or more specific gene products, including alternative splice products, and is uniquely useful in a number of therapeutic, diagnostic, and research applications. The principle behind antisense technology is that an antisense compound, e.g., an oligonucleotide, which hybridizes to a target nucleic acid, modulates gene expression activities such as transcription, splicing or translation through any one of a number of antisense mechanisms. The sequence specificity of antisense compounds makes them attractive as tools for target validation and gene functionalization, as well as therapeutics to selectively modulate the expression of genes involved in disease.
Although significant progress has been made in the field of antisense technology, there remains a need in the art for oligonucleotides, and peptide-oligonucleotide-conjugates with improved antisense or antigene performance. Such improved antisense or antigene performance includes, at least, for example: lower toxicity, stronger affinity for DNA and RNA without compromising sequence selectivity, improved pharmacokinetics and tissue distribution, improved cellular delivery, and both reliable and controllable in vivo distribution.